When I was very young we had a neighbour who was very good at getting me to talk about my family. My mother didn't like her nosiness and told me to not talk about the family anymore. I still remember what she said to me: "Lass dich nicht ausfragen!" (Don't let yourself be interrogated/quizzed.) I felt very foolish back then because I hadn't realized what the neighbour was doing. I'm sure that she asked common questions you ask a child (what my dad is doing for work was one of them) but even that was too intrusive for my mom. So I guess I can blame my aversion to small talk on my mother. I got it from her!

Also I hate talking about my weekend plans with strangers. It's not interesting for others and also not something I would ask another person because as long as those plans don't involve me I don't care what people do with their free time.